File size: 6,781 Bytes
bc3753a
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
import torch
import torch.nn as nn
import numpy as np
import os
from pytorch3d.structures import Meshes
from pytorch3d.renderer import (
    look_at_view_transform,
    PerspectiveCameras,
    FoVPerspectiveCameras,
    PointLights,
    DirectionalLights,
    Materials,
    RasterizationSettings,
    MeshRenderer,
    MeshRasterizer,
    SoftPhongShader,
    TexturesUV,
    TexturesVertex,
    blending,
)

from pytorch3d.ops import interpolate_face_attributes

from pytorch3d.renderer.blending import (
    BlendParams,
    hard_rgb_blend,
    sigmoid_alpha_blend,
    softmax_rgb_blend,
)


class SoftSimpleShader(nn.Module):
    """
    Per pixel lighting - the lighting model is applied using the interpolated
    coordinates and normals for each pixel. The blending function returns the
    soft aggregated color using all the faces per pixel.

    To use the default values, simply initialize the shader with the desired
    device e.g.

    """

    def __init__(
        self, device="cpu", cameras=None, lights=None, materials=None, blend_params=None
    ):
        super().__init__()
        self.lights = lights if lights is not None else PointLights(device=device)
        self.materials = (
            materials if materials is not None else Materials(device=device)
        )
        self.cameras = cameras
        self.blend_params = blend_params if blend_params is not None else BlendParams()

    def to(self, device):
        # Manually move to device modules which are not subclasses of nn.Module
        self.cameras = self.cameras.to(device)
        self.materials = self.materials.to(device)
        self.lights = self.lights.to(device)
        return self

    def forward(self, fragments, meshes, **kwargs) -> torch.Tensor:

        texels = meshes.sample_textures(fragments)
        blend_params = kwargs.get("blend_params", self.blend_params)

        cameras = kwargs.get("cameras", self.cameras)
        if cameras is None:
            msg = "Cameras must be specified either at initialization \
                or in the forward pass of SoftPhongShader"
            raise ValueError(msg)
        znear = kwargs.get("znear", getattr(cameras, "znear", 1.0))
        zfar = kwargs.get("zfar", getattr(cameras, "zfar", 100.0))
        images = softmax_rgb_blend(
            texels, fragments, blend_params, znear=znear, zfar=zfar
        )
        return images


class Render_3DMM(nn.Module):
    def __init__(
        self,
        focal=1015,
        img_h=500,
        img_w=500,
        batch_size=1,
        device=torch.device("cuda:0"),
    ):
        super(Render_3DMM, self).__init__()

        self.focal = focal
        self.img_h = img_h
        self.img_w = img_w
        self.device = device
        self.renderer = self.get_render(batch_size)

        dir_path = os.path.dirname(os.path.realpath(__file__))
        topo_info = np.load(
            os.path.join(dir_path, "3DMM", "topology_info.npy"), allow_pickle=True
        ).item()
        self.tris = torch.as_tensor(topo_info["tris"]).to(self.device)
        self.vert_tris = torch.as_tensor(topo_info["vert_tris"]).to(self.device)

    def compute_normal(self, geometry):
        vert_1 = torch.index_select(geometry, 1, self.tris[:, 0])
        vert_2 = torch.index_select(geometry, 1, self.tris[:, 1])
        vert_3 = torch.index_select(geometry, 1, self.tris[:, 2])
        nnorm = torch.cross(vert_2 - vert_1, vert_3 - vert_1, 2)
        tri_normal = nn.functional.normalize(nnorm, dim=2)
        v_norm = tri_normal[:, self.vert_tris, :].sum(2)
        vert_normal = v_norm / v_norm.norm(dim=2).unsqueeze(2)
        return vert_normal

    def get_render(self, batch_size=1):
        half_s = self.img_w * 0.5
        R, T = look_at_view_transform(10, 0, 0)
        R = R.repeat(batch_size, 1, 1)
        T = torch.zeros((batch_size, 3), dtype=torch.float32).to(self.device)

        cameras = FoVPerspectiveCameras(
            device=self.device,
            R=R,
            T=T,
            znear=0.01,
            zfar=20,
            fov=2 * np.arctan(self.img_w // 2 / self.focal) * 180.0 / np.pi,
        )
        lights = PointLights(
            device=self.device,
            location=[[0.0, 0.0, 1e5]],
            ambient_color=[[1, 1, 1]],
            specular_color=[[0.0, 0.0, 0.0]],
            diffuse_color=[[0.0, 0.0, 0.0]],
        )
        sigma = 1e-4
        raster_settings = RasterizationSettings(
            image_size=(self.img_h, self.img_w),
            blur_radius=np.log(1.0 / 1e-4 - 1.0) * sigma / 18.0,
            faces_per_pixel=2,
            perspective_correct=False,
        )
        blend_params = blending.BlendParams(background_color=[0, 0, 0])
        renderer = MeshRenderer(
            rasterizer=MeshRasterizer(raster_settings=raster_settings, cameras=cameras),
            shader=SoftSimpleShader(
                lights=lights, blend_params=blend_params, cameras=cameras
            ),
        )
        return renderer.to(self.device)

    @staticmethod
    def Illumination_layer(face_texture, norm, gamma):

        n_b, num_vertex, _ = face_texture.size()
        n_v_full = n_b * num_vertex
        gamma = gamma.view(-1, 3, 9).clone()
        gamma[:, :, 0] += 0.8

        gamma = gamma.permute(0, 2, 1)

        a0 = np.pi
        a1 = 2 * np.pi / np.sqrt(3.0)
        a2 = 2 * np.pi / np.sqrt(8.0)
        c0 = 1 / np.sqrt(4 * np.pi)
        c1 = np.sqrt(3.0) / np.sqrt(4 * np.pi)
        c2 = 3 * np.sqrt(5.0) / np.sqrt(12 * np.pi)
        d0 = 0.5 / np.sqrt(3.0)

        Y0 = torch.ones(n_v_full).to(gamma.device).float() * a0 * c0
        norm = norm.view(-1, 3)
        nx, ny, nz = norm[:, 0], norm[:, 1], norm[:, 2]
        arrH = []

        arrH.append(Y0)
        arrH.append(-a1 * c1 * ny)
        arrH.append(a1 * c1 * nz)
        arrH.append(-a1 * c1 * nx)
        arrH.append(a2 * c2 * nx * ny)
        arrH.append(-a2 * c2 * ny * nz)
        arrH.append(a2 * c2 * d0 * (3 * nz.pow(2) - 1))
        arrH.append(-a2 * c2 * nx * nz)
        arrH.append(a2 * c2 * 0.5 * (nx.pow(2) - ny.pow(2)))

        H = torch.stack(arrH, 1)
        Y = H.view(n_b, num_vertex, 9)
        lighting = Y.bmm(gamma)

        face_color = face_texture * lighting
        return face_color

    def forward(self, rott_geometry, texture, diffuse_sh):
        face_normal = self.compute_normal(rott_geometry)
        face_color = self.Illumination_layer(texture, face_normal, diffuse_sh)
        face_color = TexturesVertex(face_color)
        mesh = Meshes(
            rott_geometry,
            self.tris.float().repeat(rott_geometry.shape[0], 1, 1),
            face_color,
        )
        rendered_img = self.renderer(mesh)
        rendered_img = torch.clamp(rendered_img, 0, 255)

        return rendered_img